Apabila cos 20°=t,maka cotan 20°=

cos 20 = t=t/1
sin ^2.20 =1 - cos^2.20 =1-t^2
jadi sin t = V(1-t^2)
cot 20 = cos 20/ ain 20 = t /V(1-t^2)

Kelas 10 Matematika
Bab Trigonometri

cos 20° = t/1 → x/r

y = √(r² - x²)
y = √(1² - t²)
y = √(1 - t²)

cotan 20° 
= x/y
= t/√(1 - t²)